Cefsulodin is a β-lactam antibiotic that lyses actively-growing E. coli by binding specifically to the intermembrane proteins, penicillin-binding proteins 1a and b, whose transglycosylase and transpeptidase activities are involved in cell elongation and septation.Cefsulodin has been used in combination with other β-lactam antibiotics, such as cefazolin (Item No. 15776) as a strategy to circumvent drug resistance.